The invention relates to a method of producing a cage for a constant velocity universal joint. The cage is intended to guide torque transmitting balls between an outer joint part and an inner joint part. The cage includes circumferentially distributed windows positioned in one plane and window faces which are spaced along the longitudinal axis. The window faces are intended to radially, circumferentially and movably guide the inwardly and outwardly projecting balls. The plane containing the centers of the windows intersects the longitudinal axis at a right angle in the articulation center. Also, the cage includes a guiding face which enables guidance on a guiding face of one of the joint parts. The method provides first, for a blank to be formed and, after further steps, for the windows to be punched out.
A method of producing a cage for a constant velocity universal joint is known from EP 0 128 870 B1. In this publication, it is mentioned that after the blank has been formed, the outer and inner shape of the cage are subjected to a turning operation before the windows are punched out. The windows are punched out by precision punching so that subsequent machining does not take place. A disadvantage of this method is that a chip-forming machining operation still has to be carried out. Thus, the outer and inner faces may not be provided with any projections in order to allow for the turning operation.
Furthermore, German Patent Number DE 38 30 579 A1, describes a method of producing a two piece cage. The halves are produced by a chipless forming process from plate metal in a circular shape with radially extending projections. The halves are placed into a part-spherical mold and connected to one another by welding. Subsequently, the guiding faces are subjected to a grinding operation.
U.S. Pat. No. 1,040,274 proposes a method of producing a cage for ball bearings starting from a plate metal strip. A dish with a rim is formed. The dish includes a smooth inner face and outer face. Subsequently, the base of the dish is punched out. After a rim remaining in the region of the base, after the punching operation has been smoothed, oval recesses, which are open towards one end face of the cylinder, are punched out to create kind of a crown. The cage windows acquire their final shape by bending over the points of the crown. The cage windows closely enclose the balls so that they are held firmly by the cage. No provision is made for faces to radially, circumferentially and movably guide the balls in the windows.
U.S. Pat. No. 1,477,164 discloses a method of producing a cage for a roller bearing. Here, starting from a piece of plate metal material, a dish with a rim is formed. Part of the base is punched out. During a further operational step, keyhole-like apertures are punched out of the outer circumference. The tabs facing one another are bent outwardly and receive a contour which is suitable for holding the rollers.